The present invention relates to an apparatus for stopping and resetting a loom at a certain position in the event of a weft stroke which has given an indication of a breakage.
In modern looms, the stroke speed is very high. In, for example, shuttleless looms the stroke speed may be as high 600 strokes per min., and it is normally approximately 200-250 strokes per min. Shuttleless looms have rapiers either on one side of the loom or on both sides of the loom. With rapiers on only one side, the weft is gripped at the weft selector and is moved all the way across to the other side of the loom, and, with rapiers on both sides of the loom, the weft is gripped by one rapier at one side of the weft selector and is moved approximately to the middle of the loom where the weft is taken over by a rapier from the other side of the loom and moved out to that side. This operation takes place at such high speed that the first rapier is located at the selector for gripping a new weft roughly at the same time as the second rapier has reached a position at the loom edge and is to release the weft. If a weft breakage is indicated by means of a weft fork, particularly at the end of the movement of the second rapier towards the loom edge, the first rapier will have time to grip a new weft from the selector and draw this into the loom before the weft fork has had time to stop the loom. In many cases, the first rapier has had time to pass on its weft to the second rapier and this will also have had time to pull out the weft to the loom edge before the loom has stopped. In this manner that weft which gave the indication of breakage will be woven into the fabric. Thus, a program advancement, a shaft switch and possibly also a weft advancement may take place before the loom stops after a weft breakage. This entails great inconveniences and long down-times, since high-quality fabrics require resetting to the broken weft and replacement thereof by a whole weft in order that the resultant fabric need not be downgraded to a lower quality or second assortment. In the weaving operation, there is, naturally, always a balancing between the time which is consumed for resetting after one or more weft breakages during a certain running time for the loom and the quality of the weaving results.